Private Mortgage Question

Hello,

About 14 years ago my Grandparents helped me buy a house, the house is in my name and I have a private mortgage with them that I pay monthly. The house is almost paid off (15 year mortgage) and I would like to see what my options are in borrowing money from a bank using the house as collateral. Will the private mortgage be an issue? I plan on using the money on an investment rental property in hopes to acquire some good debt